Resist etch back has been used to planarize bird's head topography on the surface of semiconductor wafers. Plasma etch has also been used. These processes are time consuming and expensive
Mechanical planarization requires the introduction of polishing slurry onto the surface of a semiconductor wafer. The silicon dioxide particles are the aggregate in the polishing slurry and must be removed prior to any subsequent processing. Near total removal of residual polishing slurry is necessary to prevent problems in successive processing steps.
Depending upon prior processing steps on the semiconductor wafer, some types of clean up procedures are detrimental to the wafer. Slurry removal may be accomplished by acid etch, but the acid not only attacks the slurry aggregate but also attacks dielectric films on the wafer surface. In this instance, the prior wafer processing steps are damaged or even destroyed. Removal of the residual polishing slurry is necessary in a way that does not damage the wafer or dielectric films thereon.